Augmented combined field integral equation for low frequency problems

A new augmented combined field integral equation formulation to address the low frequency instability issue is presented. The new integral equation formulation is achieved by combing the magnetic field integral operator and the augmented electric field integral equation (A-EFIE). In addition to that, a constraint preconditioning is also introduced to fast up the convergence speed of the system matrix. Numerical examples are given to show the validity and efficiency of the proposed formulation.